1. Field of the Invention
This invention relates to apparatus for printing sheets and plates of metal wood, plastics, etc. and pipes such as steel or other metal pipes, plastic pipes and the like. More particularly, the invention relates to a printing apparatus comprising printing means which include a plurality of movable flexible endless belts incorporated in a plate drum as aligned side by side, each of the endless belts being provided with printing types on its outer peripheral surface and is displaceable for automatic typesetting or composition.
2. Description of the Prior Art
With apparatus for printing sheets and pipes, it is often required to incorporate a row of several tens of printing means into a plate drum as a unit. Furthermore, since the printing of such articles involves frequent typesetting, it is essential that the apparatus be adapted for automatic typesetting. However, an apparatus has yet to be developed which fulfils both of these requirements for printing upon sheets and pipes.
As disclosed for example in Japanese Patent Publication No. 24419/1963, printing apparatus are known in which a plurality of printing wheels, displaceable by rotation, are arranged side by side and provided with printing type on the peripheral surface thereof to serve as printing means. The apparatus disclosed in the Japanese Patent Publication merely includes printing wheels.
Accordingly, the inventor has conducted research on an apparatus comprising several tens of printing means aligned as a unit and incorporated in a plate drum which apparatus is adapted for automatic typesetting. In the course of the research, the inventor encountered a serious problem. For automatic typesetting, each printing means must be provided with a pulley or like power transmitting means which includes an electromagnetic clutch. Thus there arises the necessity of incorporating the additional transmitting means into the printing means in a compact arrangement so as to minimize the space occupied by the row of printing means. This can be met by the use of a small electromagnetic clutch for the transmitting means, but since the printing means are great in number, requiring a great number of electromagnetic clutches and similarly a great number of slip rings for feeding current to the clutches, there still remains the problem that the large number of slip rings must be provided in a compact arrangement.